1. Field of the Invention
The present invention relates to a fluorescent X-ray qualitative analytical method and in particular to a fluorescent X-ray qualitative analytical method capable of accurately analyzing a sample containing a number of elements generating a plurality of fluorescent X-rays having adjacent energies, such as Mo (molybdenum)-.alpha. and S (sulfur)-K.alpha., Mo-K.alpha., and Mo-K.alpha..sub.2 or Rh-K .alpha..sub.1, and Rh-K.alpha..sub.2, respectively.
2. Description of Related Art
In a fluorescent X-ray analyzer, as shown in FIG. 17, X-rays are incident upon a sample 2 to be measured from an X-ray generator 1 and fluorescent X-rays 3 emitted from the sample 2 are detected by means of a detector 4. Spectral data, as shown in FIG. 18, is obtained by means of a data-collecting device 41.
Since an energy value of fluorescent X-rays 3 emitted from the sample are fixed for every element contained in the sample 2, the spectral data will show peaks at energy positions corresponding to the elements contained in the sample 2. It is possible to specify the elements contained in the sample 2 from the specific positions of the peaks.
In a conventional qualitative analytical procedure, the spectral data can have a reliability from a high probability to a low probability, depending on the existence of peaks at energy positions of the fluorescent X-rays relative to the respective elements being examined. If a definite peak exists at an energy position of the fluorescent X-rays obtained from a certain element, it will be judged that the element is contained in the sample 2, while, if the peak does not exist, it is judged that the element is not contained.
However, in the case where a plurality of elements in the sample 2 may generate fluorescent X-rays having adjacent energies, such as Mo-L.alpha. and S-K.alpha., then even though it is intended to measure spectra 5 and 6 of an element showing a peak profile of fluorescent X-rays A and an element showing a peak profile of fluorescent X-rays B having peaks 8 and 9 at energy positions corresponding to these elements, as shown in FIG. 7, the peak-generating positions of the spectra 5, 6 are not detected at the peak positions 8, 9, but are rather detected as a combined peak position 10 of a measured spectrum 7 because of the resolution of the detector 4. Accordingly, even though an element showing the peak profile of fluorescent X-rays A and an element showing the peak profile of fluorescent X-rays B exist in the sample 2, the spectra 5,6 cannot be measured from the obtained spectral data so that a mistaken qualitative analytical result will occur. If a permissible range of coincidence of the peak positions is extended in order to avoid the above described disadvantages, the peak positions 8, 9 still remain adjacent to each other even in the case where merely the energy spectrum 5 exists, so that there is still a possibility that an existence of the spectrum 6 is judged.
In addition, there is also the possibility that a spectrum 25 high in importance and having a peak position (a) generated from a certain element is overlapped by another spectrum 26 having a peak position (b) and thus the spectrum 25 cannot be recognized as an independent element having the peak position (a), as shown in FIG. 19, in the spectral data obtained from the sample 2. This can lead to a misjudgment that certain elements are not contained in the sample and thus it is difficult to accurately conduct a qualitative analysis.